1. Field of the Invention
The present invention relates to a separator and a secondary battery using the same.
2. Description of the Related Art
In general, as a portable electronic device such as a video camera, a cell phone, and a portable computer is lightened and conducts high performance, research on a secondary battery as a power source for the portable electronic device is actively being made. This secondary battery may include, for example, a nickel-cadmium battery, a nickel-hydrogen battery, a nickel-zinc battery, a lithium secondary battery, and the like. Among these batteries, the lithium secondary battery may be down-sized and enlarged and also has an advantage of a high voltage and high energy density per unit weight and thus is used in many fields.
In the secondary battery, since a separator wound between electrodes may easily escape due to an area and/or weight increase according to enlargement of the separator or use of an exterior having weak shape storage stability such as a pouch type, adherence of the separator to the electrodes needs to be increased. In addition, the separator requires of excellent shape stability of the secondary battery to prevent the battery from shape change, for example, from distortion and the like due to continuous charges and discharges.
In order to improve adherence of the separator to the electrodes and heat resistance of the separator, a method of forming an organic/inorganic mixed coating layer on one surface or both surfaces of the base film of the separator has been known (Korean Registration Patent No. 10-0775310) but may not sufficiently secure desired adherence and thus not be uniformly applied to variously-sized and-shaped separators.
Accordingly, required is development of a secondary battery including a separator having adherence applicable to a secondary battery enlarged or using an exterior such as a pouch type and maintaining shape stability and the adherence after charge and discharge, an environment where the battery is actually used.